The second and third points go hand in hand, the watch's power source to the escapement is constant and by lessening the strength of the spring (hence the need for frequent winding), accumulated friction within the engaging wheels and pinions is reduced. The remontoir mechanism requires winding once every eight days. Laurans uses the term 'endless' as there is no loss of power to the watch during the re-winding process because the spring is connected directly to the train of wheels. Endless motion refers to the action of the remontoir as it periodically re-winds a light mainspring attached to the first wheel of the watch (marked 48). First is the endless motion without which nothing of this nature can be ran, secondly the equality of the periodes and thirdly the reduction of its elastic powers". The description of the remontoir opens: "There is three things to be observed in this piece of work. The high tooth count gives the timekeeper an eight-day duration. The remontoir is powered by a strong spring attached to the wheel marked as having 72 teeth and connects to the watch via a 288-toothed wheel. The remontoir mechanism is activated every 20 minutes by the two levers A1 and A2. He has replaced the standard fusee and mainspring with a spring remontoir. Laurans' innovation is the watch's source of energy. It is immediately apparent that this is not a radical re-design of the watch. The watch itself is shown with only the great wheel and centre pinion numbered - clearly it has a verge escapement and is absolutely typical of the period. The paper describes "a piece of watch work that shall goe upon sea as well as the best pendulum clock on land" and is accompanied by a simple drawing that illustrates the layout of the wheels within the watch. Decades later the required accuracy was ultimately achieved by John Harrison's watch (H4), which employs a similar re-winding mechanism, although much refined and acting only on the escapement (the heart of the watch - the ticking part).įor those of a more technical bent, here's an attempt to summarise the key points of Laurans' description. Laurans identified two key problems with the pocket watch and his design goes some way to overcome them. But the best pocket watch of the day could only keep time to within a minute a day - nowhere near the three seconds per day required to fulfil the conditions of the 1714 Longitude Act. Put simply, the pocket watch was seemingly the ideal longitude solution.
The existence of this manuscript certainly proves that John Harrison was not the first inventor of the spring remontoir. Not only is this paper the earliest reference to a spring-driven remontoir system (or re-winding mechanism) that I am aware of, but the paper might also have been a source of inspiration to John Harrison when he began planning his second marine timekeeper. If you have a cool idea for a prize that fellow IF authors might enjoy, let me know!Ĭheck out the site for more info, and I’m happy to answer any questions here or sent to aaron at looking up some of George Graham's papers at the Royal Society, I came across an intriguing paper (Cl.P/3ii/13), sent to the Society in 1721 and simply signed Laurans. The festival is always looking for prize donors. You can submit to the “Back Garden” to showcase a demo of a game you’re planning to sell, or a polished excerpt of something unfinished.Įntrants to the Main Festival can be nominated for one of two “Best In Show” ribbons, and all entries are eligible for custom “Audience Awards.” Prize donors also gift fun, unique prizes, which Main Festival entrants have a chance to receive.
#Springy thing free#
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